Engine cooling system



A. T; GREGORY ENGINE COOLING SYSTEM Jan. 29, 1946.

Filed Npv. 2, 1942 INVENTOR ALFRED TGP/SGORY BY ,WTT N Patented 194.6

mam

amount coomvo srs'ram Alfred r. Gregory, mma, my, asslgnor lllchll toF 11 Engine and Airplane Corporation,

Fanningdale, N. 1., a corporation of Maryland Application November-*2, me; Serial no. 464.2113 3 cu (or. 123-171) This invention relates to improvements in cooling systems for internal combustion engines, and relates particularly to cooling systems for aircooled aeronautical engines of the V, x, H,- or

. other in-line types.

Heretofore the cooling systems for such aircooled' airplane engines have included a scoop 'along one side of the cylinder bank into which airis forced by the movement of the airplane and the slipstream of the propeller. Plates or baiiles substantlally closing the intercylinder spaces form with the scoop a closed chamber in .which the incoming air builds up a considerable static pressure and from which it is led in intimate contact with the cylinders to cool the same, the gross area of the outlets from the scoop being less than the area of the scoop intake opening. :The bailles areso shaped on the lee side of the cylinders that a. Venturi efiect is created which increases the velocity of the spent air and tends to urge it away from the cylinders. The hot spent cooling air is then withdrawn through passages or gills by the-aspirating action of the air stream flowing over the fuselage and the wings.

The flow of air over the cylinders is caused the scoop and in the passages iorwithdrawing the heated air. Although aidedby the aforementioned Venturi and aspirating eflect, this pressure diilerential under someoperating conditions actually is relatively small, first, for the reason that it is not possible under all operating conditions to build up ahigh pressure in the scoop by means of movement of the plane and/or the slip-stream of the propeller and, second, for the reason that the aspirating action or the air stream can create, at best, but slight subatmospheric pressures on the lee side of the cylinders opposite the scoop. Moreover, the pressure diiilerential is materially decreased for thereason that the air heated by passage over the cylinders expands considerably and thereby tends to increase the pressure in the outlet or aspirating passages. For these reasons, the spent cooling air often is not removed from thecowllng as rapidly as is desired.

Under normal operating conditions, systems of the type described above operate satisfactorily,

but under abnormal conditions, such as.-high power operation of the engine, for example; on

the ground or during take oil and climb where the air speed of the airplane may be considerably less than in level flight, or at high altitudes where the density of the cooling air and thus its cooling capacity is very low there is a tendency for the engine to become overheated.

In accordance with the present invention, I have provided a system for cooling air-cooled engines, particularly of the in-line, X, H, or V actions in removing the spent cooling alrirom the cowling'and thus assures the cooling or the engine under all conditions 01' operation.

More particularly, I have provided a system' 5 including the usual scoop and baille combination for delivering cooling air under pressure to the cylinders of an aeronautical engine of the aircooled type, in which the means for withdrawing the heated air is augmented by a blower mechanism to cause a-larse volume'of cooling air to flow over the cylinders of the engine.'

As indicated above, the aspirating means alone, under some conditions, for example, at high power operation of the engine, cannot maintain such a rapid flow of air that eflicient cooling is obtained. In my system, the suction fan or blower makes up for this deficiency of the aspirating system and compensates for expansion of the heated air so that the necessary pressure drop is maintained between the airscoop and the aspirating passageways. Under these conditions, a rapid flow of air is maintained at all times. 7

For a better understanding of the present invention, reference may be had to the accompanys drawing, in which: a primarily by a diflerence in the air' pressures in V Figure 1 is a view in side elevation of a typical form ot'cooling system for an in-line type or engine with part of the cowling broken away to disclose details thereof; and

Fig. 2 is a view in section taken on line 2-4 oi Fi 1.

As illustrated in Figs. 1 and 2, the present invention isdisclosed as applied to an in-line type -of engine E having six cylinders Ill suitably provided with cooling fins Ila to. aid in the dissipation of heat therefrom. It willbe understood that the cooling system embodying the present invention may be applied equally well to V, X, H, pancake and other in-line types of engines so 40 the form of invention disclosed herein should be considered as illustrative.

As shown particularly in Fig. 2, the cowling N of the airplane is streamlined and forms a hous- .-ing enclosing the-engine. An aperture H is pro- 5 vid'ed at the front end of the cowling N forming the inlet of an airscoop i 2 for supplying air to the cylinders ll. The'airscoop l2 includes a sheet metal partition member I is having a flange 12b at the rear end thereof extending into close en- 'gagement with the cooling'ilns or the last cylinder I I in the bank. The partition member Ila extends from the valve and camshaft housing It to adjacent the crankcase C of the motor B so as to confine the air flow around the cylinders. A

second partition member It is mounted adjacent the edge 01' the aperture H opposite to th member Ila. The member It extends inwardly toa ward the first cylinder ll of the bank into engagement with the edges of the cooling iins oi type, which augments the Venturi and aspirating the first cylinder.

ample, during level flight cruising, 1 way cool the engine excessively.

tween and overlie the cylinders in order to form restricted passageways throu h which air must 1 oi the cylinder. The bailie plates and the airscoop 1 are disclosed more particularly in thew. F. Davis Q Reissue Patent No. 20,251, dated January 26, 1937.

Yiiow in contact with the Walls and radiating nns The air, after flowing aroundandbetween the conduit l0 thatc'ommunicates with the atmosphere through a gill slit or louvre 20. The air flowing along the sides 01' the cowling N will aid in withdrawing the heated air from within the 1 1 chamber i5. W l During substantially full throttle operation, the. 1 blower B may be used to cool the engine E.- However, under certain operating conditions, for ex-' In order to cool the engine properly under ,both

= conditions, I provide means for venting the chain- 1 her II directly to atmosphere and for rendering 1 the blower B ineffective. This means includes a conduit 2.! at the rear end of the chamber it that communicates with the conduit is through a valve port 23. The port 23 can be opened or 1 closed by means 01' a pivoted valve 24 that is movable between positions completely uncovering the 1 port'23 and closing the conduit i9 between the port 23 and the blower. housing I1, and completely closing the port 23 and opening the conduit ll. With this arrangement, the flow of air over and the temperature of the cylinders in can be closely regulated to maintainthem at optimum operating temperature. The valve 24 can be oberated in any suitable way, for example, bythermostatically or manually operated controls.

When the motor E is being warmed up prior to takeoii', the port 23 is closed, preferably, with the result that the blower B i rendered effective to draw air over the cylinders. Inasmuch as the. plane is not moving, the flow of air over the 'cylin- 1 ders will permit the engine to warm up gradually but will protect the engine against overheating 1 blower B has a tendency to cool the engine belownormal operating temperatures. The blower B the blower j cylinders l0, passes into a'chamberii on'the lee 3 side of the cylinders so that the heated, sp nt 3 cooling air is isolated therein. This chamber it v has a rearwardly extending duct it that communicates with the rearsideoi the housing l1 3 of a blower. ;B having an impeller i8 therein that q is driven by the engine E.or in any other suitable way, in order to withdraw heated air from the chamber ii. The air is forced from the blower. B through a laterally directed, rearwardly curved iii) maybe used to cool the engine when it is neces--' sary to operate the engine substantially at full throttle over any considerable period or time, or

ii the engine shows a tendency'to heat up because of a change of altitude or the like.

It will be understood that the shape and size be used. depending upon the type oi engine being cooled. For example, a V-type engine preferably will have the scoop disposed between the banks oi cylinders, with the bailies for directing the air around the cylinders and the chambers I! on the exterior of the banks. Moreover, the i entire cowling N may be used as a scoop, ii desired, thereby circulating cooling air around the entire engine and cooling all parts thereof.

, Therefore, the form of device disclosed herein shouldbe regarded as illustrative only and not as limiting the scopeoi the .iollowing claims.

1 I claim: v A

' 1. In a system for delivering air through a casing mounted within a cowling and enclosing one side of the cylindersoi an internal combustion engine; the combination of a'blow'er adiacent the rear of said casing having a housing and an impeller therein driven by said engine, said housto the atmosphere exterior oi said cowling and extending laterally from said housing; a third conduit connecting said casing and said second conduit,vand valve means for selectivelyconn'ect; ing said third conduit .toy and disconnecting it,

from said second conduit and closing andopenine said second conduit between said blower and said thirdconduit. v a I .2. In a cooling system for delivering air througha casing mounted within a cowling and and said port, and to enclosing one side 01' the cylinders of an internal combustion engine; the combination of a first conduit behindsaid engine having an inlet communicating with the interior of said casing and the'exterior of said cowling, an impeller driven by, said engine in said conduit, 9. second conduit communicating with said casin'gand cor'nmuniouter end of said first conduit, and valve means cooperating with said port and said firstconduit to permit said port to be opened and said'conduit to be substantially closed between. said blower close said port andopen said conduit.

3. In a system for delivering air through 9. casing disposed within a cowling and enclosing one side of the cylinders of an inline internal combustion engine; the combination of a blower having a housing and an impeller, "means extending through one side of said housing for connecting said impeller to said engine,- said housing having a centrallylocated intake port in a side opposite to said one side and a peripheral discharge Port, a first conduit connecting the interior of said casing to said intake port, a second conduit connected to' the interior of said housing through said discharge port and extending laterally to the exterior oi said cowling, a third conduit connecting the interior oi said casing to said second conduit intermediate the ends of the latter, and valve means movable selectively to one position preventing communication between'said second and third conduits and to another position closing said second conduit between said discharge port and the point of connection of said third conduit to said second conduit.

" a ALFRED T. GREGORY. 

